1. Technical Field of the Invention
The present invention relates in general to biochemical test equipment, and more particularly to alignment of sensor arrays in a biochemical testing device.
2. Description of Related Art
In a biochemical testing device for detecting and measuring luminescence, fluorescence, scattering, or absorption of analytes, one or more sensors in a sensor array is scanned to collect data from a sample. The sensors are biological or chemical substances deposited onto a substrate to form a sensor array. The biological or chemical substances can be chosen to bond with particular analytes or to react with particular analytes and change the sensor""s optical properties after such reaction. The analytes usually include proteins, peptides, or DNA. For example, a biochemical fluorescence sensor has a biological binder used capture a particular analyte and enable detection and measurement of its fluorescence characteristics. Light of a pre-determined wavelength is directed onto the sensor to excite the captured analyte. The light causes the analyte to fluoresce, and the analyte""s fluorescence is then detected and measured by a photo detector array, such as a CCD (charge coupled device) or a CMOS (complementary metal oxide semiconductor) array.
A moderately sized sensor array, for example 10 by 10, can contain 100 sensors. With so many sensors, it is difficult to direct concentrated light to each of the sensors to excite their respective analytes. The most simple way to provide light to the sensors is to flood illuminate the sensor array. However, when flood illuminating the array, much of the light is not directed at the sensors and is wasted.
Another way to provide light to the sensors is to direct a focused beam to each sensor. The light can be directed to each sensor by actively aiming the focused beam. For example, the light can be directed from a reflector system or from a diffraction grating having a diffraction pattern that matches the sensor locations. Either method, however, requires that the sensor array be precisely placed in relation to the device directing the focused light beam, or that the device directing the focused light beam have an active ability to correct for misalignment of the sensor array. Also, the specific position of each sensor must be known to correlate light emitted from a sensor with the light detected at the detector array.
In one prior art device, precision pins are registered into the sensor array. These pins are received in a structure that houses the light source and photo detector array to ensure precise placement of the sensor array relative to the light source and photo detector array. While such an alignment system is operable, it has several limitations. For example, when positioning the sensor array, care must be taken to ensure that the pins are fully received in the structure that houses the light source and photo detector array. If the pins are not fully received in the structure, the sensor array may be misaligned. Further, such pins must be precisely constructed and precisely placed with respect to the sensor array. Fabricating and placing the pins is an additional component and an additional step in manufacturing which increases the cost of constructing the sensor array.
There is a need for an improved mounting arrangement for aligning a sensor array in relation to the photo detector array or light source. Further, there is a need for a system to make precise alignment of the sensor array with the incident light less critical, thus compensating for slight misalignments.
The exemplary embodiments of the present invention encompass a sensor alignment system and a biochemical testing device having an improved mounting arrangement to align the sensor array in relation to a photo detector array and light source.
The biochemical testing device has a sensor cartridge with at least one sensor. At least one micro-lens is coupled to the sensor such that the micro-lens focuses light into the sensor. The micro-lens has an outer surface. The testing device has an alignment structure with a mating profile adapted to receive the outer surface of the micro-lens to position the sensor cartridge laterally. A light source illuminates the at least one micro-lens. At least one optical detector is positioned to detect light emitted from the at least one micro-lens.
The invention encompasses a sensor alignment system for aligning a sensor array in a biochemical testing device. The Sensor array has one or more micro lenses. The sensor alignment system has an alignment structure positioned in relation to the biochemical testing device and adapted to receive the one or more micro-lenses of the micro-lens array to align the biochemical testing device with the sensor array.
The invention also encompasses a biochemical testing device for receiving a sensor cartridge. The sensor cartridge having at least one sensor and at least one micro-lens coupled to the sensor. The testing device has an alignment structure having a mating profile adapted to receive the outer surface of the micro-lens to position the sensor cartridge laterally. A light source is positioned in relation to the alignment structure for illuminating the at least one micro-lens. The testing device also has at least one photo-detector positioned in relation to the alignment structure to detect light emitted from the at least one micro-lens.